A major advance in the mass testing of automotive vehicle brakes is disclosed in a series of previously filed applications assigned to the assignee of this application. In the Cline, U.S. Pat. No. 3,899,916 issued Aug. 19, 1975, relating to "Recorder and Computer Type Brake Analyzer and Method," a complete brake testing system is described in which a series of accurately controlled brake tests are systematically performed to provide brake performance data which is then evaluated by a computer to determine whether the brakes are malfunctioning. In the Clayton, Sr. et al., U.S. Pat. No. 3,877,299 issued Apr. 15, 1975, relating to "Brake Pedal Actuator," a removable brake pedal actuator is disclosed which is placed on the vehicle floorboard and which uses a differential air pressure power unit to apply force to the brake pedal until a predetermined level of brake effort is reached, manual force applied by the operator being utilized to provide a reference force, or reaction point, which holds the brake pedal actuator in position. In recently filed Asmus and Wickersham application relating to "Brake Testing Apparatus and Method Incorporating Hydraulic Position-Sensitive Subsystem," a hydraulic sybsystem for the brake testing apparatus is disclosed which functions as a stroke-limiting memory unit and as a position-holding means during the brake test sequence.
The present invention relates to an actuator unit for moving a pedal or treadle during testing, which actuator unit provides significant improvements over the one disclosed in U.S. Pat. No. 3,877,299, and which has been developed to solve problems identified as a result of experience gained in working with the earlier unit.
Two of the primary goals in any mass vehicle testing apparatus are: (a) universal applicability to the wide variety of designs of vehicles and their control systems, and (b) maximum testing speed, including both time of testing a given vehicle and, perhaps more importantly, time of transferring the testing apparatus from one vehicle to the next. It is the furtherance of these goals on which the present invention is primarily focused.
In the operation of the earlier systems, difficulty has been encountered in adjusting the portable actuator units to all makes of vehicles. Also in a brake testing sequence wherein the two front brakes are tested separately from the two rear brakes, in order to permit the driver to move the vehicle from front testing position to rear testing position, it has generally been necessary to remove the portable actuator unit from the vehicle after the testing of the front brakes, or to include a special brake control mechanism operative while the vehicle is being moved. This has been true because the brake pedal has not usually been accessible to the driver with the portable actuator unit in testing position.